New advanced oxidation technologies of water and wastewater treatment (part 1)(foreign publications review)

Summary

With the increase in population and industrial water consumption satisfying the demand for drinking water becomes a very pressing issue. This problem can be solved by using innovation process flow schemes of wastewater treatment. Advanced oxidation technologies are among them, i. e. homogenous and heterogenous photocatalytic processes, ozonation, Fenton’s process options, ultrasonic treatment, wet oxidation, electrochemical processes, oxidation in supercritical water, plasma processes, ferrate and persulfate technologies, ionization radiation and microwave treatment. Hydroxyl radicals play key role in these processes. Photocatalytic processes proceed in the presence of catalysts with titanium dioxide (TiO2) being most efficient among them. The processes proceed in photocatalytic reactors in the presence of suspended catalyst and supported catalyst. In the process of water disinfection the synergistic effect is reached at combining advanced oxidation technologies and chlorination. Fenton’s process is based on the use of Fenton’s reagent, i. e. mixture of Fe2+ salt (catalyst) and hydrogen peroxide. Optimal рН value of 2.8–4 is the basic parameter of this process. Ozonation process proceeding in the presence of hydroxyl radicals originating from chemical transformation of ozone at 2.8 hydroxyl radical reduction potential is considered. Optimal formation of hydroxyl radicals is provided in ozonizers with hydrogen peroxide dosing device (Peroxone process). Ozonation in the process of UV-irradiation; ozonation in the process of UV-irradiation in the presence of hydrogen peroxide, ozonation in combination with ultrasound (Sonozone process) are considered. The use of advanced oxidation technologies in wastewater treatment produces positive results that provide for satisfying the water demand. (To be continued).